The disclosure relates to semiconductor devices and the manufacturing of semiconductor devices. More specifically, the disclosure relates to improved back side metallization for integrated circuit device wafers and die.
Integrated circuits are used in computing devices such as, but not limited to, smart phones, tablets, wearables, laptops, desktops, internet servers, printers, and other devices. Integrated circuits can have very dense circuitry and can operate at very high frequencies to provide ever-improving levels of performance. Some devices may have multiple processor cores and/or very large memory arrays on relatively small die. In operation, such devices can produce heat in excess of 100 watts. If the heat is allowed to build up on the die, the performance of the integrated circuit may be degraded and/or the life of the integrated circuit may be significantly shortened.
In some integrated circuits, a thermally conductive layer is applied to the back side of the die and bonded to a heat sink, such a package lid. The package lid can have larger area than the back side of the die and may be exposed to a convective flow of air to remove heat from the package lid. The thermally conductive layer can provide a thermal path through which the heat may flow from the die to the package lid to dissipate from the package lid.
The flow of heat through the heat path can be significantly reduced if the bond between the thermally conductive layer and the back side of the die fails. Thus, good adhesion between the back side of the die and the thermally conductive layer is an important factor in removing the heat build-up and consequently, in the reliability of the integrated circuit device.